The invention relates to a robot with at least one at least partly externally positioned protective hose, particularly a cable guidance hose receiving a supply cable for robot tools.
In the case of multiaxial robots with several parts swivellable relative to one another and in particular robot arms, in the case of robot movements spacing changes of the individual parts occurs, which must be taken into account especially in the case of at least partly externally positioned protective hoses for guiding supply cables for elements and mainly tools of the robot. The latter must on the one hand be in a position to take up length changes and on the other must be loaded or strained as little as possible during robot movements so as to ensure a high stability and prevent premature damage.
The palletizing robot has four active axes (three basic axes and one hand axis). The active hand axis is rotation axis A6. A5 is passive and is moved synchronously with A2 and A3 by a push rod 1A acting in an articulation 13. In order to ensure the cable guide length reserves necessary for taking up or absorbing length changes, it is e.g. known to guide the supply cables in essentially circular loops in the vicinity of the axes of the robot arms (DE 198 17 605) or to connect them to a robot hand by means of a rotary passage or duct. Whereas the latter is complicated and costly, the sole guidance of the supply cables in loops restricts mobility or swivellability of the robot, particularly the robot hand.
Therefore the problem of the invention in the case of a robot of the aforementioned type is to ensure an improved cable guidance which, as a result of a significant length reserve, does not impair robot mobility and simultaneously does not or only slightly strains the supply cables or the protective hose receiving the latter.
In the case of a robot of the aforementioned type this problem is solved according to the invention by a winding guide positioned in the vicinity of a tool assembly flange for winding and unwinding the protective hose length necessary as a function of tool movements.
As a result of the construction according to the invention with protective hose length changes caused by robot movements, said hose is not drawn in or tightened in uncontrolled manner, but is instead wound and unwound in controlled manner by rotating the winding guide. This leads to a substantially unrestricted freedom of movement of the robot and in particular a high rotation angle of the holding device for the tool, which e.g. permits a tool rotation by at least 270Ø in each direction. The protective hose loads and strains cause by tensile and compressive forces are reduced by the in particular frictional winding and unwinding with respect to the winding guide. Finally, robot compactness is increased, because the winding guide avoids the cable being wound in uncontrolled manner around the arm and hand during the rotation of A6, which is in particular problematical with large rotation angles.
In order to ensure a correct winding and unwinding of the protective hose when tool movements occur, preferably the winding guide has two substantially congruent, spaced disks, between which the protective hose is wound and in particular the disk spacing roughly corresponds to or slightly exceeds the protective hose thickness.
In a preferred construction the rotation axis of the winding guide is positioned parallel to the axis of a robot hand having the tool assembly flange and in particular is coaxial to the axis having the largest necessary swivel angle.
According to a preferred development, with the winding guide are associated guide rollers, which guide the protective hose at least along a robot arm articulated to the robot hand. Preferably there are two guide rollers guiding the protective hose substantially parallel to the robot arm and whereof one is mounted in the area of the robot axes located at the robot arm ends. The guide rollers are appropriately substantially parallel to the robot axes located on the robot arm and to which the robot arm is terminally articulated. This ensures a permanently close guidance of the protective hose along the robot, in that the hose, e.g. during tool movements, is wound over the winding guide and via the guide rollers follows at least along the robot arm articulated to the robot hand.
The protective hose is preferably guided in a loop around the robot axis of the robot arm remote from the robot hand and in this case preferably at least one guide element is provided guiding the protective hose in the circumferential direction of the robot axis of the robot arm remote from the robot hand and which can e.g. be constructed in the manner of a hollow cylinder receiving the hose.
To permanently ensure a close guidance of the protective hose on the robot arm, together with a completely satisfactory winding and unwinding of the protective hose by means of the winding guide, the protective hose is wound in loop form around the A3 axis and is preferably pretensioned in the winding direction. In a preferred development a return spring is provided for this purpose and can e.g. be located on the guide element for guiding the protective hose in the circumferential direction of the robot hand-remote robot axis of the robot arm articulated thereto. As a result of this construction the protective hose length reserves necessary for a satisfactory freedom of movement can be taken up by the winding guide by winding the hose.